论文
Flow Behavior Of Tailings Slurry
1. Introduction
Tailings slurry plays an important role in resource development and environmental protection for many countries throughout the world. Tailings are solid residues generated from a process such as ore extraction, beneficiation or chemical processing. In some instances, this material can be stored in a pond or dam structure designed to minimize release of particulates into the environment. In other cases, disposal of the material i8s via pipeline to another pond or dam facility down stream. In either situation, predicting and assessing the flow behaviour of the tailings slurry will help in the design of the storage or deposition facility, ensuring a safe and efficient operation.
This paper is focused on the flow behavior of tailings slurry. An overview of the properties of tailings will be provided and their impact on the rheological characteristics of the slurry discussed. Various testing techniques and equipment used to measure rheology will be outlined and their advantages and limitations considered. The importance of adjusting the physical parameters of the slurry such as pH, solids concentration and temperature in order toperform effective testing will also be highlighted. The paper will conclude with recommendation for further research.
2. Properties of Tailings Slurry
Tailings slurry is a complex mixture of solid particles and water. The physical and chemical properties of the slurry will depend on the type of ore being processed, the geological conditions and the processing techniques used. Generally, tailings slurry contains iron and other metals, organic compounds, and other impurities. The type and concentration of these components may vary depending on the specific ore and processing techniques employed.
The physical properties of tailings slurry can have a significant impact on its flow behaviour. The size and shape of the solid particles will determine the size of the aggregates formed and the packing density of the material. The particle size distribution (PSD), the particle shape aspect ratio and the tortuosity of the solid compacts can directly influence the viscosity of the material. The presence of a thin liquid film between particles can also affect the viscosity.
Furthermore, the surface charge of the solid particles can interact with the electrolyte ions in the liquid to produce a zeta potential that affects the stability of the slurry. This can lead to changes in the rheological characteristics of the tailings slurry such as its viscoelasticity and plasticity. The electrolyte concentration and type, as well as the pH of the slurry can all impact the zeta potential.
3. Testing Techniques
A range of methods and techniques can be used to measure the rheological characteristics of tailings slurry. These measurements are important for the design of storage and disposal facilities and the prediction of flow behaviour.
Viscometry is one of the most commonly used testing techniques for the measurement of the rheology of tailings slurry. This method involves measuring the viscosity of the solution with a variety of instruments such as plate viscometers, rotating viscometers, Tornado viscometers, and rheometers. The viscosity profile of the slurry can be determined from these measurements and the flow behaviour of the material in a pipe can be estimated.
The measurement of particle size and shape is also important for assessing the rheology of tailings slurry. Laser diffraction, sieving, and imaging techniques are commonly used for this purpose. These techniques allow the analysis of the particle size, shape, and distribution at various points in the system.
Dynamic rheology is another technique used to measure the rheological behaviour of tailings slurry. This technique involves the measurement of the viscosity of the solution over an imposed stress cycle. This information can be used to assess the variation of viscosity and elasticity of the material with time.
Finally, the electrical and optical properties of tailings slurry can be analysed using conductivity, absorbency, and fluorescence measurement techniques. These techniques provide information on the physical and chemical properties of the material and can be used to assess the stability and flow behaviour of the slurry.
4. Advantages and Limitations
The use of testing techniques for measuring the rheology of tailings slurry has several advantages. These tests provide accurate and reliable information on the physical and chemical properties of the material. They also enable the estimation of pipe flow behaviour and the prediction of settling characteristics.
However, there are several limitations to the use of these testing methods. The accuracy of the results may be affected by the presence of impurities and electrolytes in the mixture and the size and shape of the solid particles. In addition, the testing equipment may not be able to measure all aspects of the slurry’s rheology.
5. Adjusting the Physical Parameters
The rheological characteristics of tailings slurry can be adjusted to improve the accuracy of the testing techniques. The most important parameters to adjust are the pH, the solids concentration, and the temperature.
Increasing the pH of the solution can reduce the electrical repulsion caused by the zeta potential and improve the accuracy of the testing results. Adjusting the solids concentration can also reduce the zeta potential and increase the accuracy of the results.
Finally, varying the temperature of the slurry can affect its viscosity and rheology. This can help to identify optimal flow conditions for the material.
6. Recommendations for Further Research
Further research should be conducted to improve the accuracy of testing techniques for measuring the rheological characteristics of tailings slurry. It is important to develop methods for more accurately measuring the size and shape of the solid particles and their packing density.
In addition, research should be conducted on the interaction between the electrical and optical properties of the slurry and its rheology. This could provide a better understanding of the effect of zeta potential on the viscoelasticity and plasticity of the material.
Finally, research should be conducted to improve the accuracy of the measure of viscosity of tailings slurry. This could involve the development of new instruments or the modification of existing ones to better account for the complex rheology of the slurry.
7.Conclusion
This paper presented an overview of the flow behavior of tailings slurry. The physical and chemical properties of tailings slurry were discussed, and various testing techniques and equipment used to measure the rheology of the material were outlined. The advantages and limitations of these testing methods were considered and suggestions were made for adjusting the physical parameters of the slurry in order to improve the accuracy of the results. Recommendations for further research were also provided.
